We spent months examining porting Nisus Writer 6.5 to Carbon. We did not do this because for us, Cocoa offered more features for the same amount of engineering work.

As an example, if we had ported to Carbon, our users still wouldn't have had features like Zoom, which comes for free with Cocoa. Then there is the change to Intel-based Macs. That would represent another huge engineering effort, as you cannot run Carbon applications natively without significant work.

By using the Cocoa frameworks, we were able to add features that would have taken much longer to develop in Classic Nisus Writer. Zoom, Spell Checking As You Type, Unicode, and Toolbar customization to name a few. Plus, we added support for the new Intel-based machines in a few days, as opposed to months.

We know this has alienated some customers, and for that we apologize. But we had to look at the long term, not the short term, and our only choice was Cocoa.